液力耦(ou)合器(qi)是液力傳動(dong)(dong)元件，又稱液力聯軸器(qi)，它是利(li)用液體的動(dong)(dong)能來傳遞功率的一種(zhong)動(dong)(dong)力式液壓傳動(dong)(dong)設(she)備。將(jiang)其安裝在異步(bu)電(dian)動(dong)(dong)機(ji)和工作機(ji)（如風機(ji)、水泵等）之間來傳遞兩者的扭矩，可以在電(dian)機(ji)轉速(su)(su)恒定的情況下，無(wu)級調節工作機(ji)的轉速(su)(su)，并具有空載啟動(dong)(dong)，過載保護，易于(yu)實現自(zi)動(dong)(dong)控制等特點。

1、液力耦(ou)合器(qi)分(fen)類

液(ye)力耦合器有(you)三種基本類型(xing)：普通(tong)型(xing)、限矩型(xing)和調(diao)速(su)型(xing)。調(diao)速(su)型(xing)液(ye)力耦合器又可分為(wei)進(jin)口調(diao)節(jie)式(shi)和出口調(diao)節(jie)式(shi)。其調(diao)速(su)范圍對恒轉矩負載約為(wei)3：1，對(dui)離心式風機約為4：1，最大可達5：1.。

進口調節式液力耦合器又(you)稱旋(xuan)轉殼體式液力耦合器，特(te)點是結構簡單(dan)緊湊(cou)、體積小、質量輕，自帶(dai)旋(xuan)轉貯油(you)外(wai)殼，無(wu)需專(zhuan)門油(you)箱(xiang)和(he)供油(you)泵，但因耦合器本(ben)身(shen)無(wu)箱(xiang)體支撐，旋(xuan)轉部件的質量由電(dian)(dian)機和(he)工作機的軸分擔(dan)，對(dui)電(dian)(dian)機增加(jia)了(le)附加(jia)載荷，同時(shi)調速時(shi)間較長。一(yi)般多用(yong)于功率小于500kw和轉速低于1500r/min的場合(he)。

出口調(diao)節式(shi)液力耦合器也(ye)稱箱體式(shi)液力耦合器。進(jin)口油量不變，工作腔充油量改變，耦合器輸出轉速也(ye)發生變化(hua)，它(ta)的特(te)點是(shi)本(ben)身有(you)堅實的箱體支撐，因此適合于(yu)高轉速、大功率(lv)，調(diao)速過程時(shi)間(jian)短(duan)，但外形尺寸大，輔助設備多。

1、 液力耦(ou)合器(qi)的工作原理(li)

調速(su)(su)型(xing)液(ye)(ye)力耦合器是以液(ye)(ye)體(ti)(ti)為介質傳遞功率(lv)的(de)(de)一種液(ye)(ye)力傳遞裝置。運轉(zhuan)時，原動(dong)機帶(dai)(dai)動(dong)泵輪(lun)(lun)(lun)旋轉(zhuan)，液(ye)(ye)體(ti)(ti)在泵輪(lun)(lun)(lun)葉(xie)片帶(dai)(dai)動(dong)下因離心(xin)力作用(yong)，由泵輪(lun)(lun)(lun)內側(ce)流(liu)向外(wai)緣，形(xing)成高壓高速(su)(su)液(ye)(ye)流(liu)沖向渦輪(lun)(lun)(lun)葉(xie)片，使渦輪(lun)(lun)(lun)跟隨泵輪(lun)(lun)(lun)作同向旋轉(zhuan)，液(ye)(ye)體(ti)(ti)在渦輪(lun)(lun)(lun)中(zhong)由外(wai)緣流(liu)行內側(ce)被迫減壓減速(su)(su)，然后流(liu)入(ru)泵輪(lun)(lun)(lun)，在這種循(xun)環(huan)中(zhong)，泵輪(lun)(lun)(lun)將原動(dong)機的(de)(de)機械能(neng)(neng)(neng)轉(zhuan)變(bian)成工作液(ye)(ye)的(de)(de)動(dong)能(neng)(neng)(neng)和勢能(neng)(neng)(neng)，而渦輪(lun)(lun)(lun)則將液(ye)(ye)體(ti)(ti)的(de)(de)動(dong)能(neng)(neng)(neng)和勢能(neng)(neng)(neng)又轉(zhuan)變(bian)成輸出軸的(de)(de)機械能(neng)(neng)(neng)，從而實(shi)現(xian)(xian)能(neng)(neng)(neng)量的(de)(de)柔性傳遞。通過改變(bian)工作腔中(zhong)工作液(ye)(ye)體(ti)(ti)的(de)(de)充(chong)滿度就可以在原動(dong)機轉(zhuan)速(su)(su)不變(bian)的(de)(de)條件下，實(shi)現(xian)(xian)被驅動(dong)機械的(de)(de)無級調速(su)(su)。

2、 調速變頻(pin)器的分類

變(bian)頻(pin)(pin)技術，簡單說就是(shi)(shi)把(ba)(ba)(ba)直流(liu)(liu)(liu)電(dian)(dian)(dian)逆變(bian)成(cheng)(cheng)(cheng)不同(tong)頻(pin)(pin)率(lv)的交(jiao)流(liu)(liu)(liu)電(dian)(dian)(dian)，或(huo)是(shi)(shi)把(ba)(ba)(ba)交(jiao)流(liu)(liu)(liu)電(dian)(dian)(dian)變(bian)成(cheng)(cheng)(cheng)直流(liu)(liu)(liu)電(dian)(dian)(dian)再逆變(bian)成(cheng)(cheng)(cheng)不同(tong)頻(pin)(pin)率(lv)的交(jiao)流(liu)(liu)(liu)電(dian)(dian)(dian)，或(huo)是(shi)(shi)把(ba)(ba)(ba)直流(liu)(liu)(liu)電(dian)(dian)(dian)變(bian)成(cheng)(cheng)(cheng)交(jiao)流(liu)(liu)(liu)電(dian)(dian)(dian)再把(ba)(ba)(ba)交(jiao)流(liu)(liu)(liu)電(dian)(dian)(dian)變(bian)直流(liu)(liu)(liu)電(dian)(dian)(dian)。總之這一切都是(shi)(shi)電(dian)(dian)(dian)能不發生變(bian)化，而只有(you)頻(pin)(pin)率(lv)的變(bian)化，變(bian)頻(pin)(pin)器就是(shi)(shi)改變(bian)電(dian)(dian)(dian)源(yuan)頻(pin)(pin)率(lv)的設備。變(bian)頻(pin)(pin)器的種類很多，可(ke)以按(an)變(bian)換環節、儲能方式、工作原理和用途進行(xing)分類。

（1）按變換(huan)環節：交(jiao)(jiao)(jiao)一交(jiao)(jiao)(jiao)變頻器。把頻率(lv)(lv)固定的(de)交(jiao)(jiao)(jiao)流(liu)電(dian)直(zhi)接(jie)變換(huan)成頻率(lv)(lv)和(he)電(dian)壓(ya)連(lian)(lian)續(xu)(xu)可(ke)調的(de)交(jiao)(jiao)(jiao)流(liu)電(dian)。交(jiao)(jiao)(jiao)一直(zhi)一交(jiao)(jiao)(jiao)變頻器。先把頻率(lv)(lv)固定的(de)交(jiao)(jiao)(jiao)流(liu)電(dian)整流(liu)成直(zhi)流(liu)電(dian)，再把直(zhi)流(liu)電(dian)逆變成頻率(lv)(lv)連(lian)(lian)續(xu)(xu)可(ke)調的(de)交(jiao)(jiao)(jiao)流(liu)電(dian)。

（2）按直流環節的儲能(neng)方(fang)式分：電流型(xing)變(bian)頻器；電壓型(xing)變(bian)頻器。

（3）按工作原理分：U/f控制(zhi)變頻器。U/f控(kong)制的基本特點是對變(bian)頻(pin)器輸出的電壓(ya)和頻(pin)率(lv)同時進行(xing)控(kong)制，通過(guo)使(shi)用U/f的值(zhi)保(bao)持一(yi)定而得到所需的轉矩特(te)性；轉差頻(pin)率控(kong)制變(bian)頻(pin)器，轉差頻(pin)率控(kong)制方式是對U/f控(kong)(kong)(kong)制(zhi)的一(yi)種改進，這種控(kong)(kong)(kong)制(zhi)需(xu)要由安裝在電(dian)(dian)(dian)動機上的速度(du)(du)傳感器(qi)監測出(chu)(chu)電(dian)(dian)(dian)動機的轉(zhuan)(zhuan)速，構成速度(du)(du)閉(bi)環，速度(du)(du)調節器(qi)的輸(shu)出(chu)(chu)為轉(zhuan)(zhuan)差頻率(lv)，而變頻器(qi)的輸(shu)出(chu)(chu)頻率(lv)則由電(dian)(dian)(dian)動機的實際(ji)轉(zhuan)(zhuan)速與所需(xu)轉(zhuan)(zhuan)差頻率(lv)之和決定；矢量(liang)(liang)控(kong)(kong)(kong)制(zhi)變頻器(qi)。矢量(liang)(liang)控(kong)(kong)(kong)制(zhi)是(shi)一(yi)種高性能(neng)異步(bu)電(dian)(dian)(dian)動機控(kong)(kong)(kong)制(zhi)方式，它的基本(ben)思(si)路是(shi)：將異步(bu)電(dian)(dian)(dian)動機的定子電(dian)(dian)(dian)流分為產(chan)生(sheng)磁(ci)場的電(dian)(dian)(dian)流分量(liang)(liang)和與其垂(chui)直的產(chan)生(sheng)轉(zhuan)(zhuan)矩(ju)的電(dian)(dian)(dian)流分量(liang)(liang)，并(bing)分別加以控(kong)(kong)(kong)制(zhi)；直接轉(zhuan)(zhuan)矩(ju)控(kong)(kong)(kong)制(zhi)變頻器(qi)。

（4）按(an)用(yong)途分：通(tong)(tong)用(yong)變(bian)(bian)(bian)(bian)(bian)頻(pin)器(qi)(qi)。所謂通(tong)(tong)用(yong)變(bian)(bian)(bian)(bian)(bian)頻(pin)器(qi)(qi)，是(shi)指能(neng)(neng)與(yu)普通(tong)(tong)的(de)籠(long)型異步(bu)電(dian)動(dong)(dong)機配套(tao)使用(yong)，能(neng)(neng)適應(ying)各種不同(tong)性質(zhi)的(de)負載，并具有多(duo)種可供(gong)選擇功能(neng)(neng)的(de)變(bian)(bian)(bian)(bian)(bian)頻(pin)器(qi)(qi)；高性能(neng)(neng)專用(yong)變(bian)(bian)(bian)(bian)(bian)頻(pin)器(qi)(qi)。高性能(neng)(neng)專用(yong)變(bian)(bian)(bian)(bian)(bian)頻(pin)器(qi)(qi)主(zhu)要應(ying)用(yong)于對電(dian)動(dong)(dong)機的(de)控制要求(qiu)較高的(de)系(xi)統，與(yu)通(tong)(tong)用(yong)變(bian)(bian)(bian)(bian)(bian)頻(pin)器(qi)(qi)相比，高性能(neng)(neng)專用(yong)變(bian)(bian)(bian)(bian)(bian)頻(pin)器(qi)(qi)大多(duo)數采(cai)用(yong)矢量控制方式，驅動(dong)(dong)對象(xiang)通(tong)(tong)常(chang)是(shi)變(bian)(bian)(bian)(bian)(bian)頻(pin)器(qi)(qi)廠家指定的(de)專用(yong)電(dian)動(dong)(dong)機；高頻(pin)變(bian)(bian)(bian)(bian)(bian)頻(pin)器(qi)(qi)，在超精密加工和高性能(neng)(neng)機械中，常(chang)常(chang)要用(yong)到高速電(dian)動(dong)(dong)機，為了(le)滿足(zu)這(zhe)些(xie)高速電(dian)動(dong)(dong)機的(de)驅動(dong)(dong)要求(qiu)，出現了(le)采(cai)用(yong)PAM控制方式的高頻變頻器，其輸出頻率可達到(dao)3kHz。